Is he wanting to order this stuff online or buy it locally? For online buying, can't beat Ebay Motors for best pricing. Just make sure he's buying name brand stuff from reputable dealers and not knock-off "JDM" Ebay junk. Best to purchase from Ebay stores with a "Buy it Now" option; that way he won't have to bid.

As for other sites, well, I like this one: www.importrp.com. They seem to have a pretty decent selection and pricing isn't too bad. You can check out our vendors down in the vendor forum as well...

EDIT: Just for clarification, I'm talking about buying NEW parts on Ebay, not used stuff...